While I found a question asked for android (http://stackoverflow.com/questions/3189188/gps-location-without-service) I couldn't find one for iOS so I thought I'd ask it. Especially since it seems to be possible in Android (see link).
I'm wondering if there's anyway to get location without a service provider. For example, I have access to an older iPhone 3GS but clearly don't want to pay any fees just to test my location services code.
I'm thinking that since location should be determinable via WIFI then maybe the only difference would be the increased precision of GPS. Maybe that'll be enough.
I actually got the answer by posting at Apple's devforums.
Basically, Location Services are independent of GPS - the APIs are identical regardless of device.
Which makes sense. Essentially, the only difference with actual GPS-based location is precision.
What fees are you worried about ? If it's mobile data charges then just switch off mobile data - the gps will still work fine!
Related
I've been researching a possible iOS-based app, developed in Unity, that would require a high-degree of positional accuracy (centimeters).
I expect I would need to connect, from the app, to an external GPS device using Bluetooth (or similar) and obtain NMEA sentences (or similar) containing location data.
My research has brought me to RTK, which is extremely accurate. From what I've seen already, it seems that normally GPS receivers which offer this operate themselves at normal GPS precision (2-2.5m). The correction to a high-accuracy location happens in software on a connected computer or tablet with a connection to an NTRIP server.
Assuming what I've said is correct, does anyone know of a GPS device that performs this RTK correction on the GPS device itself? Ideally I could just connect with Bluetooth or similar and get NMEA (or equivalent) data with high-accuracy location.
It may also be that I'm thinking about this incorrectly. On iOS, assuming there is an 3rd party app performing the RTK calculations, is there a standard way to obtain that high-accuracy location? Alternatively, are there GPS vendors that supply SDKs that would allow me to get to where I need to go?
Thanks very much,
Kieran
There is a recent module from U-Blox named ZED-F9P which has internal processing and is faster then RTKLib. Check this blog for performance
You can buy a board like ArduSimple's simpleRTK2B with an XBee module for WiFi/Blutooth or something similar from Sparkfun. You could also wait for the development board from U-Blox which is not yet available.
Is it possible to make sure that GPS positions an iOS app is getting are real, and they are not fake locations illegitimately provided somehow, for example, by means of another app such as LocationHolic?
Thanks!
You could theoretically do some ip number geo lookup (e.g. How does geographic lookup by IP work?), but that's not entirely reliable (e.g. VPNs), so I'd be hesitant to dispute someone's location on the basis of that. Given that locationholic is for jailbroken devices, perhaps validate location information against ip-derived location info if, and only if, the app is running on jailbroken device. For info re ip number based geo lookup or identifying if a device is jailbroken, I'm expert in neither, but both topics are covered well elsewhere on StackOverflow or can be answered with a google search.
In short, I suspect that locations are reliable on non-jail-broken phones. Regarding "Find My iPad/iPhone" on jail-broken phones, I can't speak to that, but all rules of reliability and security are thrown out of the window on jail-broken devices, so you can't rely on it.
I've been googling this problem, but haven't gotten the wording right.
Basically I'm looking for an API, or some seeds of guidance in how I would go about writing a program where you get push notified if someone is in the same area as you based on GPS coordinates. In short: a realtime 4square not based on checking-in but based on GPS.
Part of me feels like this is something Apple may frown upon, but if the user is notified and making the decision to run the app, perhaps not.
Thanks in advance.
You're looking for the Bluetooth Bonjour type notifications found in GameKit. This has nothing to do with GPS and is instead based of short range radio (Bluetooth) which advertises itself using a zero conf protocol. The APIs basically give you the ability to broadcast your service (eg. "MyGame") over bluetooth and listen for others potentially broadcasting the same service.
If you're talking about geographic vicinity, you'll need to set up a central server where each device can register its location, and which will provide locations of nearby devices. A service like FourSquare does exactly this kind of thing.
Another way to look at 'vicinity' is network vicinity. You could have each device advertise itself via Bonjour and look for other devices doing the same.
How would I go about figuring the position of someone inside (or outside) of a given area (such as a building) using assisted GPS with IOS app?
Is it possible to have it accurate enough withing a few feet?
Is this the right way to go about it?
Is it possible to utilize more than one wifi connection in the calculation?
Your app can use the Core Location framework to determine the device location. Core Location will use whatever hardware is at its disposal to determine the device location to the degree that you request. For example, some devices have WiFi but no GPS; others have WiFi, GPS, and cellular radios. Future devices may have other location technologies built in.
The point is that as an application programmer, you don't worry about that. Instead, you say: "give me a location that's accurate to 100 meters" or "let me know when the device has moved from the current spot by more than 10 meters" or "give me the location with the best accuracy you can manage."
Again, take a look at Apple's Core Location documentation to get a better idea of how it all works.
If you're looking to track a device with, say, 1-meter resolution inside a building, you're not likely to get that from Core Location. There's been research on triangulating position using known locations of WiFi transceivers, but nothing that's implemented in any commercial smart phone that I know of. I don't believe that iOS gives you easy access to the data you'd need to do this, so it's probably not a possibility. You could, however, go the other way: program several WiFi receivers around the building to listen for any nearby devices, use that information to triangulate the devices' positions, and then make that information available via some web service.
I'm trying to write a simple GPS based application for my BB 8800 (with Airtel, India).
But for some reason my code getLocation(timeout) always returns with a non-valid location (only after timing out). I tried different combinations of criteria parameters with no success.
I'm pretty sure that the problem is not with my code because even the BlackBerry GPS demo application does not work. However, my GPS receiver is working fine because "Wayfinder", a maps application that came bundled with my BB, works fine.
To test it further, I tried running SpotFinder and Google Maps. But they did not work either. Google Maps could determine location using cell tower info but not GPS.
Here are some more details about my environment,
1. Phone Model: BlackBerry 8800
2. Carrier: AirTel (India)
3. Device Version: 4.2.168 (Platform 2.3.0.54)
Can my carrier block it? [I spoke with AirTel technical support but they wouldn't budge to help developers]
Thanks In Advance
Some carriers (like Verizon US) blocked GPS for third party applications. Others just enabled GPS for a white list of applications (mostly their own) but deny access to GPS for all others.
It seems your provider is doing such things.
Can your carrier block it? Absolutely, I don't know about in India, but in the U.S. some carriers can and do restrict applications from accessing the GPS if they are not "approved." That seems quite likely given the scenario you described.